Process for producing adamantane compound

ABSTRACT

It is made possible to efficiently produce adamantane and analogues thereof, namely a hydrocarbon having an adamantane structure by a process which comprises isomerizing a tricyclic saturated hydrocarbon having ten or more carbon atoms in the presence of a solid-acid catalyst containing one or two or more metals selected from among the metals belonging to group VIII in the Periodic Table (group 8 to 12 in the new Periodic Table), wherein one or two or more monocyclic saturated hydrocarbons are added to the tricyclic saturated hydrocarbon having ten or more carbon atoms.

TECHNICAL FIELD

The present invention relates to a process for producing a hydrocarbonhaving an adamantane structure by isomerizing a tricyclic saturatedhydrocarbon having ten or more carbon atoms.

BACKGROUND ART

Adamantane is a compound which is obtained by isomerizing, in thepresence of a catalyst, trimethylene norbornane (hereinafter sometimesreferred to as “TMN”) obtainable by hydrogenating dicyclopentadiene(hereinafter sometimes referred to as “DCPD”). In an industrial processfor producing the same, aluminum chloride has heretofore been employedas a catalyst. However, in the case of producing adamantane in thepresence of aluminum chloride as a catalyst, it is necessary to use alarge amount thereof and besides, the catalyst is not reusable becauseof complex formation with heavy components during the course ofreaction. Accordingly, the foregoing process, when being employedtherefor, brings about the formation of a large amount of waste aluminumcomponents, whereby the waste treatment thereof gives rise to a problemof environmental pollution. In addition, high corrosiveness of aluminumchloride necessitates the use of an expensive corrosion-resistantmaterials of construction. Moreover, aluminum chloride, when usedtherefor, causes the resultant adamantane to be colored and therebybrings about such disadvantages that recrystallizing step anddecolorizing step by means of activated carbon or the like are requiredand hence, a post treatment is made intricate.

On the other hand, a solid-acid catalyst is known which comprises anactive metal such as platinum, rhenium, nickel or cobalt each beingsupported by impregnation method on zeolite that has been subjected tocation exchange by the use of a rare earth metal or an alkaline earthmetal {refer to Japanese Patent Publication No. 2909/1977 (Showa 52)}.However, even in the case where the aforesaid solid-acid catalyst isemployed, the yield of adamantane is low, unless hydrogen chloride isallowed to coexist therewith, for instance, conversion of TMN of 79.5%,selectivity to adamantane of 10.1% and yield of adamantane of 8.0%.Therefore, hydrogen chloride is indispensable for the isomerization, buthigh corrosiveness of hydrogen chloride necessitates the use of anexpensive corrosion-resistant materials of construction {(refer toJapanese Patent Publication No. 2909/1977 (Showa 52)}.

DISCLOSURE OF THE INVENTION

An object of the present invention is to provide a process forefficiently produce adamantane and analogues thereof by the use of asolid-acid catalyst instead of hydrogen chloride.

As the result of intensive extensive research and investigation made bythe present inventors, it has been found that the above-mentioned objectis achieved by carrying out the isomerization reaction in the presenceof a monocyclic saturated hydrocarbon. Thus the present invention hasbeen accomplished on the basis of the foregoing findings andinformation.

Specifically, the present invention provides a process for producingadamantane and analogues thereof, namely a hydrocarbon having anadamantane structure which process comprises isomerizing a tricyclicsaturated hydrocarbon having ten or more carbon atoms in the presence ofa solid-acid catalyst containing one or two or more metals selected fromamong the metals belonging to group VIII in the Periodic Table (group 8to 12 in the new Periodic Table), wherein one or two or more monocyclicsaturated hydrocarbons are added to the tricyclic saturated hydrocarbonhaving ten or more carbon atoms.

THE MOST PREFERRED EMBODIMENT TO CARRY OUT THE INVENTION

As mentioned hereinabove, the catalyst to be used in the productionprocess according to the present invention is a solid-acid catalystcontaining one or two or more metals selected from among the metalsbelonging to group VIII in the Periodic Table (group 8 to 12 in the newPeriodic Table). The metals belonging to group VIII in the PeriodicTable (group 8 to 12 in the new Periodic Table) are not specificallylimited. Examples thereof include iron, cobalt, nickel, ruthenium,rhodium, palladium, osmium, iridium and platinum, of which platinum ispreferable.

Examples of the solid-acid catalyst to be used in the production processaccording to the present invention include various types of zeolites(type A, type B, type L, type X, type Y, type ZSM and the like) astypical species, and metal oxides such as silica-alumina, alumina andheteropolyacid. Of these X or Y type zeolite is preferable.

In the following, some description will be given of the case wherezeolite is used as the solid-acid catalyst. The catalyst to be used inthe production process according to the present invention can beproduced by allowing zeolite to be incorporated with one or two or moremetals selected from among the metals belonging to group VIII in thePeriodic Table (group 8 to 12 in the new Periodic Table) by means of anion exchange method or an impregnation method.

In the case of an ion exchange method, the catalyst can be produced bybringing any of metals as mentioned above in the state of, for instance,an aqueous solution of a metal salt or a metal complex salt into contactwith zeolite so as to subject any of the metals to ion exchange with thecation site (for instance, H⁺, NH₄ ⁺) in the X or Y type zeolite, dryingand calcining the zeolite thus ion exchanged. In the case of animpregnation method, the catalyst can be produced by mixing any of themetals in the state of an aqueous solution of a metal salt or a metalcomplex salt with zeolite, and then evaporating the resultant mixture todryness by the use of a rotary evaporator or the like so that the metalis impregnated into and supported on the zeolite. The content of the oneor two or more metals selected from among the metals belonging to groupVIII in the Periodic Table (group 8 to 12 in the new Periodic Table) inthe solid-acid catalyst to be used in the production process accordingto the present invention is not specifically limited, but is preferablyat least 0.1% by weight.

The catalyst may be of an optional shape such as powder or granule.

The starting material to be used in the production process according tothe present invention is a tricyclic saturated hydrocarbon having ten ormore carbon atoms, which is specifically exemplified by trimethylenenorbornane (tetrahydrodicyclopentadiene); dimethyltrimethylenenorbornane; perhydroacenaphthene; perhydrofluorene; perhydrophenalene;1,2-cyclopentanoperhydronaphthalene; perhydroanthracene,perhydrophenanthrene; and 9-methylperhydroanthracene. Theabove-exemplified tricyclic saturated hydrocarbon can be produced by awell-known process, for instance, by the hydrogenation of acorresponding unsaturated hydrocarbon.

In the present invention, the isomerization reaction of theabove-mentioned tricyclic saturated hydrocarbon is put into practice inthe presence of a monocyclic saturated hydrocarbon, that is, acycloparaffin. The monocyclic saturated hydrocarbon is preferably asaturated hydrocarbon having 3 to 8 ring members, and may be substitutedwith a lower alkyl group as the case may be. Preferable monocyclicsaturated hydrocarbons are exemplified by cyclopentane, cyclohexane,ethylcyclohexane and methylcyclohexane. Of these are preferablecyclohexane, ethylcyclohexane and the mixture of the above two.

The amount of the monocyclic saturated hydrocarbons to be added to thetricyclic saturated hydrocarbon is not specifically limited, but may beselected according to various circumstances usually in the range of 0.01to 3 mol, preferably 0.1 to 2 mol per one mol of the tricyclic saturatedhydrocarbon.

The isomerization reaction in the production process according to thepresent invention is carried out in the presence of the above-mentionedcatalyst under the conditions including a reaction temperature in therange of 150 to 500° C., preferably 200 to 400° C. and reaction pressureof atmospheric pressure or under pressure. The reaction system may beeither continuous system or batchwise system. The reaction is preferablycarried out in the presence of hydrogen from the viewpoint ofenhancement of adamantane yield.

The amount of the catalyst to be used is 0.01 to 2, preferably 0.05 to 1in the case of batchwise system.

The regeneration of the catalyst can be carried out by a burning methodin air.

In what follows, the present invention will be described in more detailwith reference to comparative examples and working examples, whichhowever shall never limit the present invention thereto.

EXAMPLE 1

Na-form Y type zeolite (hereinafter referred to as “NaY”) which had aSiO₂/Al₂O₃ molar ratio of 5.0 in an amount of 235 g was suspended bystirring in 2000 g of pure water. To the resultant suspension was added114 g of ammonium sulfate to dissolve in the suspension and thereafterthe mixture was heated to 60° C. with stirring for 30 minutes. Theresultant slurry was filtered, and then washed by pouring 2500 g of purewater. The washed cake was dried at 110° C. overnight, and calcined inair at 600° C. for 3 hours to obtain a primary ion exchanged product.The resultant primary ion exchanged product was suspended in 2000 g ofpure water. To the resultant suspension was added 228 g of ammoniumsulfate to dissolve in the suspension and thereafter the mixture washeated to 95° C. with stirring for 30 minutes. Thereafter the suspensionwas washed with 2000 g of pure water. The foregoing procedure wasrepeated three times, and the secondary ion exchanged product thusobtained was termed NH₄-form Y type zeolite (hereinafter referred to as“NH₄Y”). The NH₄Y in an amount of 178 g was placed in a tubular vessel,subjected to steaming at 510° C. for 30 minutes in 100% steam, andsuspended by stirring in 2000 g of pure water. To the steamed NH₄Y wasadded 283 g of 25% sulfuric acid over a period of 30 minutes. Then, theresultant NH₄Y slurry was heated to raise the liquid temperature up to95° C., subjected to an acid treatment for one hour, filtered followedby washing, and dried at 110° C. overnight to obtain H-form ultrastableY type zeolite (hereinafter referred to as “HUSY”) which had a latticeconstant of 24.47 and a SiO₂/Al₂O₃ molar ratio as obtained from Breck'sformula of 10.4. The HUSY in an amount of 170 g was suspended bystirring in 2000 g of pure water. To the suspension was added 180 g of1.71% aqueous solution of tetraammineplatinum chloride with stirring at60° C. for 30 minutes. The resultant mixed suspension was filtered,washed, and dried at 110° C. overnight to obtain a 0.93% Pt/HUSY.

The catalyst in an amount of 4 g which had been obtained through theforegoing procedure was packed in a tubular reactor made of stainlesssteel (SUS), and was calcined at 300° C. for 3 hours under atmosphericpressure in a stream of air. After the atmosphere in the reactor wasreplaced with nitrogen, the catalyst was reduced with hydrogen at 300°C. for 3 hours under atmospheric pressure in a stream of hydrogen.Thereafter, supply to the reactor, of mixed solution of TMN andethylcyclohexane (hereinafter sometimes abbreviated to “ECH”) having aTMN:ECH ratio by weight of 1:1 along with hydrogen was commenced so asto proceed with continuous isomerization reaction under the reactionconditions of 250° C., 2 MPa, weight hourly space velocity (WHSV) being1.2 h⁻¹ (on TMN basis) and hydrogen/TMN molar ratio being 2. Thereaction results after 40 hours from the start of TMN supply are givenin Table 1.

In this connection, conversion of TMN and selectivity to adamantane wereeach calculated by the following formula, respectively:

-   -   Conversion of TMN=(1−weight of TMN after reaction/weight of TMN        before reaction)×100    -   Selectivity to adamantane={weight of formed adamantane/(weight        of TMN before reaction−weight of TMN after reaction)}×100

COMPARATIVE EXAMPLE 1

The procedure in Example 1 was repeated to prepare and pretreat acatalyst and proceed with the reaction except that ECH was not added toTMN as the starting material and the reaction was conducted at a WHSV of2.4 h⁻¹ (on TMN basis). The reaction results after 40 hours from thestart of TMN supply are given in Table 1.

EXAMPLE 2

NaY which had a SiO₂/Al₂O₃ molar ratio of 5.0 in an amount of 235 g wassuspended by stirring in 2000 g of pure water. To the resultantsuspension was added dilute sulfuric acid to adjust the pH of thesuspended slurry to 5.5. Aside therefrom, 246 g of lanthanum nitratehexahydrate was dissolved in 500 g of warm water. The aqueous solutionof lanthanum nitrate thus obtained was gradually mixed with thesuspended slurry. Thereafter, the resultant mixture was heated to 90°C., stirred for 30 minutes, then filtered and washed. The washed cakewas dried at 110° C. overnight, and calcined at 600° C. for 3 hours.

The powder was again suspended by stirring in 2000 g of pure water, tothe resultant slurry was added 228 g of ammonium nitrate, and themixture was stirred at 95° C. for 30 minutes, filtered and washed. Thewashed cake was again suspended in 2000 g of pure water, and thesuspended slurry was subjected to an ion exchange operation twiceconsecutively. Subsequently, the resultant ion exchanged product wasdried at 110° C. overnight. The dried product was placed in a tubularvessel, subjected to steaming at 510° C. for 30 minutes in 100% steam,and the steamed powder thus obtained was suspended in 2000 g of purewater. The suspended slurry was gradually incorporated with 32 g of 25%sulfuric acid, heated at 95° C. for 30 minutes, then filtered andwashed. The washed cake was again suspended in 2000 g of pure water. Tothe resultant suspension was added 180 g of 1.71% aqueous solution oftetraammineplatinum chloride with stirring at 60° C. for 30 minutes. Theresultant mixed suspension was filtered, washed, and dried at 110° C.overnight to obtain a La-containing Y type zeolite on which 0.87%platinum was supported by means of ion exchange (hereinafter sometimesabbreviated to “0.87% Pt/LaUSY”).

The catalyst in an amount of 4 g which had been obtained through theforegoing procedure was packed in a tubular reactor made of stainlesssteel (SUS), and was calcined at 300° C. for 3 hours under atmosphericpressure in a stream of air. After the atmosphere in the reactor wasreplaced with nitrogen, the catalyst was reduced with hydrogen at 300°C. for 3 hours under atmospheric pressure in a stream of hydrogen.Thereafter, supply to the reactor, of mixed solution of TMN andethylcyclohexane (hereinafter sometimes abbreviated to “ECH”) having aTMN:ECH ratio by weight of 1:1 along with hydrogen was commenced so asto proceed with continuous isomerization reaction under the reactionconditions of 250° C., 2 MPa, weight hourly space velocity (WHSV) being1.2 h⁻¹ (on TMN basis) and hydrogen/TMN molar ratio being 2. Thereaction results after 40 hours from the start of TMN supply are givenin Table 1.

COMPARATIVE EXAMPLE 2

The procedure in Example 2 was repeated to prepare and pretreat acatalyst and proceed with the reaction except that ECH was not added toTMN as the starting material and the reaction was conducted at a WHSV of2.4 h⁻¹ (on TMN basis). The reaction results after 40 hours from thestart of TMN supply are given in Table 1.

EXAMPLE 3

The procedure in Example 2 was repeated to prepare and pretreat acatalyst and proceed with the reaction except that the reactiontemperature was set on 300° C. The reaction results after 40 hours fromthe start of TMN supply are given in Table 1.

EXAMPLE 4

The procedure in Example 3 was repeated to prepare and pretreat acatalyst and proceed with the reaction except that cyclohexane(hereinafter sometimes abbreviated to “CH”) was added to TMN in place ofECH. The reaction results after 40 hours from the start of TMN supplyare given in Table 1.

COMPARATIVE EXAMPLE 3

The procedure in Comparative Example 2 was repeated to prepare andpretreat a catalyst and proceed with the reaction except that thereaction temperature was set on 300° C. The reaction results after 40hours from the start of TMN supply are given in Table 1.

EXAMPLE 5

The procedure in Example 2 was repeated to prepare and pretreat acatalyst and proceed with the reaction except that the reactiontemperature and reaction pressure were set on 325° C. and 5 MPa,respectively. The reaction results after 40 hours from the start of TMNsupply are given in Table 1.

COMPARATIVE EXAMPLE 4

The procedure in Example 5 was repeated to prepare and pretreat acatalyst and proceed with the reaction except that ECH was not added toTMN as the starting material and the reaction was conducted at a WHSV of2.4 h⁻¹ (on TMN basis). The reaction results after 40 hours from thestart of TMN supply are given in Table 1.

EXAMPLE 6

The procedure in Example 5 was repeated to prepare and pretreat acatalyst and proceed with the reaction except that the reactiontemperature was set on 350° C. The reaction results after 40 hours fromthe start of TMN supply are given in Table 1.

COMPARATIVE EXAMPLE 5

The procedure in Example 6 was repeated to prepare and pretreat acatalyst and proceed with the reaction except that ECH was not added toTMN as the starting material and the reaction was conducted at a WHSV of2.4 h⁻¹ (on TMN basis). The reaction results after 40 hours from thestart of TMN supply are given in Table 1.

TABLE 1 Reaction Reaction Conversion Selectivity temperature pressure ofTMN To adamantane Catalyst Additive (° C.) (MPa) (% by weight) (% byweight) Example 1 Pt/HUSY ECH 250 2 99.7 10.0 Comparative ″ None ″ ″46.4 10.0 Example 1 Example 2 Pt/LaUSY ECH ″ ″ 91.8 15.1 Comparative ″None ″ ″ 37.1 13.0 Example 2 Example 3 ″ ECH 300 ″ 43.4 21.5 Example 4 ″CH ″ ″ 17.8 30.2 Comparative ″ None ″ ″ 21.6 15.5 Example 3 Example 5 ″ECH 325 5 99.5 15.5 Comparative ″ None ″ ″ 91.2 15.3 Example 4 Example 6″ ECH 350 ″ 99.7 13.2 Comparative ″ None ″ ″ 95.2 12.8 Example 5

As can be clearly seen from Table 1, the use of ECH leads to markedenhancement of the conversion of TMN, while the use of CH leads tomarked enhancement of the selectivity to adamantane.

INDUSTRIAL APPLICABILITY

By carrying out the isomerization reaction of a tricyclic saturatedhydrocarbon in the presence of a monocyclic saturated hydrocarbonaccording to the present invention, it is made possible to markedlyenhance the conversion of the tricyclic saturated hydrocarbon as thestarting material as well as the selectivity to adamantane. In addition,since no use is made of a highly corrosive substance such as hydrogenchloride at the time of production, it is made possible to efficientlyproduce adamantane and analogues thereof at a low cost, dispensing withthe use of a corrosion resistant material in production equipment.

1. A process for producing adamantane and analogues thereof, namely ahydrocarbon having an adamantane structure which process comprisesisomerizing a tricyclic saturated hydrocarbon having ten or more carbonatoms in the presence of a solid-acid catalyst containing one or two ormore metals selected from among the metals belonging to group VIII inthe Periodic Table (group 8 to 12 in the new Periodic Table),characterized in that one or two or more monocyclic saturatedhydrocarbons are added to the tricyclic saturated hydrocarbon having tenor more carbon atoms.
 2. The process for producing adamantane andanalogues thereof according to claim 1, wherein the monocyclic saturatedhydrocarbon is cyclohexane, ethylcyclohexane or a mixture thereof. 3.The process for producing adamantane and analogues thereof according toclaim 1, wherein the metal belonging to group VIII in the Periodic Table(group 8 to 12 in the new Periodic Table) is platinum.
 4. The processfor producing adamantane and analogues thereof according to claim 1,wherein the solid-acid catalyst is Y type zeolite.